1. Field of the Invention
The present invention relates to a method for making a sound-insulating load-bearing floor.
In particular, the present invention relates to a method for making a sound-insulating load-bearing floor, said method comprising the step of applying over said load-bearing floor a sound-insulating material including at least one rubber in a subdivided form and at least one binding agent.
In a further aspect, the present invention also relates to a sound-insulating material including at least one rubber in a subdivided form and at least one binding agent.
In a still further aspect, the present invention also relates to a building structure including at least one load-bearing floor, said load-bearing floor comprising a sound-insulating material including at least one rubber in a subdivided form and at least one binding agent.
2. Description of the Related Art
In building constructions, in particular in building constructions including two or more stories, it is known to include a sound-insulating material on the load-bearing floor of the upper floors. The sound-insulating material minimizes the pressure of sound generated into a room and traveling downward through the load-bearing floor. Sound-insulating material functions by reflecting sound waves, absorbing sound waves, and/or disrupting sound waves.
Conventional sound-insulating materials comprise pre-formed sheets of cork, asphalt, or other materials such as, for example, foamed polyethylene, foamed polyurethane.
However, said sound insulating materials may show some disadvantages.
For example, the asphalt typically comprises about 80% by weight of tar, the remainder including clay, solvents, and other fillers. One disadvantage of the asphalt is that upon aging, it tends to harden. It also hardens in cold weather. When asphalt hardens, it tends to crack if the floor expands or contracts (e.g. as a consequence of temperatures changes). Similarly, since cork comprises a matrix of particles pressed together, the cork also tends to develop cracks if the floor expands or contracts (e.g. as a consequence of temperatures changes).
Moreover, the application of pre-formed sheets only seldom allows to make a continuous coating layer of a sound-insulating material onto the surface of the load-bearing floor. As a matter of fact, in particular at the joining zones between the different pre-formed sheets which do not always fit perfectly together, an acoustic bridge between the load-bearing floor and the covering floor may occur. Furthermore, when applying the covering floor onto the surface of the pre-formed sheets, said pre-formed sheets may move so causing the formation of an acoustic bridge between the load-bearing floor and the covering floor. The travel of the sounds through said acoustic bridges negatively affect their sound-insulating properties.
Other sound-insulating materials have been already suggested in the art.
For example, International Patent Application WO 02/48478 relates to a light soundproof floor-filling structure for filling the space between a floor surface and the level of the laying plane of the walking-on floor covering. Said soundproof floor-filling structure consists of a mixture of concrete as air-hardening binder and a given amount of grains of resin materials which may be selected from polyvinyl resins, polyethylene, polypropylene, polyvinylchloride, caoutchouc, rubbers in general, polycarbons, silicon resins, plastics of different kinds. Metal elements such as copper and tin may be present as either pure metal or alloys. The above-mentioned structure is said to have the following features: lightness, soundproofing, compactness, workability, mechanical strength and environmental compatibility.
International Patent Application WO 00/26485 relates to an acoustic insulating material with a filler which is mainly made of granules of a sound-deadening component, mixed with a binding agent, such that an almost coherent mass is formed. Said filler mainly contains rubber granules. Said binding agent is made on the basis of polyurethane and preferably consists of a polyurethane glue. A sound-insulating sprung floor provided with the above-mentioned insulating material and resting on a load-bearing floor, and a method for making such a floor, are also disclosed.
French Patent Application FR 2,221,465 relates to a material made from waste rubber particles, in particular waste rubber particles derived from tyres, and a synthetic elastomeric binding agent, preferably a moisture-hardening isocyanate or polyisocyanate or a two-component polyurethane. Said binding agent is of cellular structure and fills only partly the spaces between the rubber particles. The abovementioned material is said to be suitable as a floor underlay.
According to the Applicant, the sound-insulating materials as described above may have some disadvantages.
For example, when concrete is used as an air-hardening binder, the sound-insulating materials has low sound-insulating properties because of the stiffness of the concrete. On the other end, the use of isocyanates or polyisocyanates as binding agents, has to be avoided because of the toxicity of said substances which lead to risks for both the environment and the health of the operators. Moreover, in the case of fire, isocyanates, polyisocyanates or polyurethanes may release cyanidric acid.